This invention relates to a fifth wheel coupling device for coupling a fifth wheel trailer male end to a conventional trailer hitch ball and further to an apparatus for coupling a fifth wheel trailer hitch male end to a trailer hitch ball located in the trunk compartment of a motor vehicle.
A fifth wheel trailer hitch mechanism is a popular means of rotatably connecting a trailer to a motor vehicle. These trailers are commonly used with pickup trucks, wherein the fifth wheel plate is pivotally mounted in the truck bed and a fifth wheel male end is mounted to a beam extending from the trailer. Such a conventional fifth wheel trailer hitch mechanism is shown in U.S. Pat. No. 3,392,992 to Baker et al. The Baker patent discloses a fifth wheel-type trailer having an extension beam which is mounted to a fifth wheel plate in the truck bed by means of a fifth wheel male end.
In touring with a trailer, it is often desirable to use an automobile as the towing vehicle, rather than a pickup truck. An automobile permits more passengers to be carried by the towing vehicle and also provides an enclosed trunk compartment for carrying luggage. As well, many individuals prefer to own an automobile in preference to a pickup truck and only have an automobile available to tow a trailer.
In the past, trailers have been connected to automobiles by using a standard ball hitch-type coupling system attached to the rear bumper of the automobile. A fifth wheel type trailer could not be properly attached to a ball hitch-type coupling system without some modification, as the fifth wheel male end of the trailer is generally too high to be properly coupled at the level of the automobile bumper. One method of solving this problem and thereby coupling a fifth wheel-type trailer to an automobile is to provide a support system in or adjacent the trunk of the automobile and to couple the fifth wheel male end of the trailer to the support system.
Several coupling systems have been devised to couple a fifth wheel type trailer to a support system in the trunk compartment of an automobile. This permits an automobile to be used to tow a fifth wheel-type trailer. Such a coupling system serves at least two purposes. Firstly, such a system generally provides for coupling in a position which is raised from the floor of the trunk compartment and couples the trailer to the automobile at the proper level for towing the trailer in a suitable horizontal orientation. This raised position also permits the trailer to pivot with respect to the automobile without interference with the rear of the automobile. Secondly, the positioning of the coupling system in or adjacent the trunk compartment moves the weight of the trailer on the rear of the automobile to a position closer to the rear axle of the automobile, which improves the load bearing capabilities of the automobile.
Examples of coupling mechanisms used to couple an automobile to a fifth wheel type trailer are disclosed in U.S. Pat. No. 3,801,1352 to Winter and also in U.S. Pat. No. 4,256,3232 to McBride. These apparatuses generally provided a rigid frame assembly having a means for coupling a fifth wheel type trailer to a corresponding mating end attached to the trunk compartment of the passenger motor vehicle. There are several difficulties with these types of coupling mechanisms. Firstly, as seen in McBride, if the trunk lid is to enclose the trunk, the coupling mechanism must be positioned above the trunk lid for proper clearance between the trailer and the rear deck of the motor vehicle. This relatively high orientation of the coupling means causes instability as the coupling mechanism (and the weight of the trailer thereon) is at a relatively high centre of gravity compared to the motor vehicle. In Winter the centre of gravity of the coupling mechanism is lower than McBride, being in the trunk compartment of the vehicle. However, in Winter, in order to accommodate this lower centre of gravity for the coupling mechanism, the trunk lid must be completely removed from the vehicle and is attached to the underside of the forward extension portion of the trailer. Consequently, with the Winter apparatus the entire trunk compartment is open to the elements in order to permit coupling and proper clearance of the coupler and trailer extension beam for normal pivotal movement of the trailer, relative to the motor vehicle.
Consequently, there is a need for a fifth wheel trailer coupling mechanism which may be attached to the trunk compartment of a motor vehicle, without removal of the trunk lid, through a relatively small opening in the trunk lid. Furthermore, there is a need for a coupler device to couple a fifth wheel type trailer to the coupling mechanism in the trunk compartment which may fit through the opening and permit rotation of the trailer, relative to the motor vehicle. There is also a need for a coupling mechanism having a portion which may be raised from the trunk compartment through the opening to an area above the trunk lid to enable the user to couple the coupler device to the trailer with the trunk lid closed and which portion may be lowered into the trunk compartment through the opening for positioning within the trunk compartment when the trailer is towed to lower the centre of gravity of the coupler device to facilitate more stable and secure towing of the trailer. As well, there is a need for a sealable cap to be positioned about the trunk lid opening when the trailer is coupled to the automobile to prevent rain water and other foreign matter from entering the trunk compartment when the trailer is coupled to the automobile. There is also a need for a sealable cap to be positioned in and cover the trunk lid opening when the trailer has been detached from the motor vehicle to prevent foreign materials such as rain water from entering the trunk compartment through the opening.